/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

package com.rmsl.juce;

import java.lang.Runnable;
import java.io.*;
import java.net.URL;
import java.net.HttpURLConnection;
import java.util.concurrent.CancellationException;
import java.util.concurrent.Future;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Callable;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.atomic.*;

public class JuceHTTPStream
{
    public JuceHTTPStream(String address, boolean isPostToUse, byte[] postDataToUse,
                          String headersToUse, int timeOutMsToUse,
                          int[] statusCodeToUse, StringBuffer responseHeadersToUse,
                          int numRedirectsToFollowToUse, String httpRequestCmdToUse) throws IOException
    {
        isPost = isPostToUse;
        postData = postDataToUse;
        headers = headersToUse;
        timeOutMs = timeOutMsToUse;
        statusCode = statusCodeToUse;
        responseHeaders = responseHeadersToUse;
        totalLength = -1;
        numRedirectsToFollow = numRedirectsToFollowToUse;
        httpRequestCmd = httpRequestCmdToUse;

        connection = createConnection(address, isPost, postData, headers, timeOutMs, httpRequestCmd);
    }

    public static final JuceHTTPStream createHTTPStream(String address, boolean isPost, byte[] postData,
                                                        String headers, int timeOutMs, int[] statusCode,
                                                        StringBuffer responseHeaders, int numRedirectsToFollow,
                                                        String httpRequestCmd)
    {
        // timeout parameter of zero for HttpUrlConnection is a blocking connect (negative value for juce::URL)
        if (timeOutMs < 0)
            timeOutMs = 0;
        else if (timeOutMs == 0)
            timeOutMs = 30000;

        for (; ; )
        {
            try
            {
                JuceHTTPStream httpStream = new JuceHTTPStream(address, isPost, postData, headers,
                        timeOutMs, statusCode, responseHeaders,
                        numRedirectsToFollow, httpRequestCmd);

                return httpStream;
            } catch (Throwable e)
            {
            }

            return null;
        }
    }

    private final HttpURLConnection createConnection(String address, boolean isPost, byte[] postData,
                                                     String headers, int timeOutMs, String httpRequestCmdToUse) throws IOException
    {
        HttpURLConnection newConnection = (HttpURLConnection) (new URL(address).openConnection());

        try
        {
            newConnection.setInstanceFollowRedirects(false);
            newConnection.setConnectTimeout(timeOutMs);
            newConnection.setReadTimeout(timeOutMs);

            // headers - if not empty, this string is appended onto the headers that are used for the request. It must therefore be a valid set of HTML header directives, separated by newlines.
            // So convert headers string to an array, with an element for each line
            String headerLines[] = headers.split("\\n");

            // Set request headers
            for (int i = 0; i < headerLines.length; ++i)
            {
                int pos = headerLines[i].indexOf(":");

                if (pos > 0 && pos < headerLines[i].length())
                {
                    String field = headerLines[i].substring(0, pos);
                    String value = headerLines[i].substring(pos + 1);

                    if (value.length() > 0)
                        newConnection.setRequestProperty(field, value);
                }
            }

            newConnection.setRequestMethod(httpRequestCmd);

            if (isPost)
            {
                newConnection.setDoOutput(true);

                if (postData != null)
                {
                    OutputStream out = newConnection.getOutputStream();
                    out.write(postData);
                    out.flush();
                }
            }

            return newConnection;
        } catch (Throwable e)
        {
            newConnection.disconnect();
            throw new IOException("Connection error");
        }
    }

    private final InputStream getCancellableStream(final boolean isInput) throws ExecutionException
    {
        synchronized (createFutureLock)
        {
            if (hasBeenCancelled.get())
                return null;

            streamFuture = executor.submit(new Callable<BufferedInputStream>()
            {
                @Override
                public BufferedInputStream call() throws IOException
                {
                    return new BufferedInputStream(isInput ? connection.getInputStream()
                            : connection.getErrorStream());
                }
            });
        }

        try
        {
            return streamFuture.get();
        } catch (InterruptedException e)
        {
            return null;
        } catch (CancellationException e)
        {
            return null;
        }
    }

    public final boolean connect()
    {
        boolean result = false;
        int numFollowedRedirects = 0;

        while (true)
        {
            result = doConnect();

            if (!result)
                return false;

            if (++numFollowedRedirects > numRedirectsToFollow)
                break;

            int status = statusCode[0];

            if (status == 301 || status == 302 || status == 303 || status == 307)
            {
                // Assumes only one occurrence of "Location"
                int pos1 = responseHeaders.indexOf("Location:") + 10;
                int pos2 = responseHeaders.indexOf("\n", pos1);

                if (pos2 > pos1)
                {
                    String currentLocation = connection.getURL().toString();
                    String newLocation = responseHeaders.substring(pos1, pos2);

                    try
                    {
                        // Handle newLocation whether it's absolute or relative
                        URL baseUrl = new URL(currentLocation);
                        URL newUrl = new URL(baseUrl, newLocation);
                        String transformedNewLocation = newUrl.toString();

                        if (transformedNewLocation != currentLocation)
                        {
                            // Clear responseHeaders before next iteration
                            responseHeaders.delete(0, responseHeaders.length());

                            synchronized (createStreamLock)
                            {
                                if (hasBeenCancelled.get())
                                    return false;

                                connection.disconnect();

                                try
                                {
                                    connection = createConnection(transformedNewLocation, isPost,
                                            postData, headers, timeOutMs,
                                            httpRequestCmd);
                                } catch (Throwable e)
                                {
                                    return false;
                                }
                            }
                        } else
                        {
                            break;
                        }
                    } catch (Throwable e)
                    {
                        return false;
                    }
                } else
                {
                    break;
                }
            } else
            {
                break;
            }
        }

        return result;
    }

    private final boolean doConnect()
    {
        synchronized (createStreamLock)
        {
            if (hasBeenCancelled.get())
                return false;

            try
            {
                try
                {
                    inputStream = getCancellableStream(true);
                } catch (ExecutionException e)
                {
                    if (connection.getResponseCode() < 400)
                    {
                        statusCode[0] = connection.getResponseCode();
                        connection.disconnect();
                        return false;
                    }
                } finally
                {
                    statusCode[0] = connection.getResponseCode();
                }

                try
                {
                    if (statusCode[0] >= 400)
                        inputStream = getCancellableStream(false);
                    else
                        inputStream = getCancellableStream(true);
                } catch (ExecutionException e)
                {
                }

                for (java.util.Map.Entry<String, java.util.List<String>> entry : connection.getHeaderFields().entrySet())
                {
                    if (entry.getKey() != null && entry.getValue() != null)
                    {
                        responseHeaders.append(entry.getKey() + ": "
                                + android.text.TextUtils.join(",", entry.getValue()) + "\n");

                        if (entry.getKey().compareTo("Content-Length") == 0)
                            totalLength = Integer.decode(entry.getValue().get(0));
                    }
                }

                return true;
            } catch (IOException e)
            {
                return false;
            }
        }
    }

    static class DisconnectionRunnable implements Runnable
    {
        public DisconnectionRunnable(HttpURLConnection theConnection,
                                     InputStream theInputStream,
                                     ReentrantLock theCreateStreamLock,
                                     Object theCreateFutureLock,
                                     Future<BufferedInputStream> theStreamFuture)
        {
            connectionToDisconnect = theConnection;
            inputStream = theInputStream;
            createStreamLock = theCreateStreamLock;
            createFutureLock = theCreateFutureLock;
            streamFuture = theStreamFuture;
        }

        public void run()
        {
            try
            {
                if (!createStreamLock.tryLock())
                {
                    synchronized (createFutureLock)
                    {
                        if (streamFuture != null)
                            streamFuture.cancel(true);
                    }

                    createStreamLock.lock();
                }

                if (connectionToDisconnect != null)
                    connectionToDisconnect.disconnect();

                if (inputStream != null)
                    inputStream.close();
            } catch (IOException e)
            {
            } finally
            {
                createStreamLock.unlock();
            }
        }

        private HttpURLConnection connectionToDisconnect;
        private InputStream inputStream;
        private ReentrantLock createStreamLock;
        private Object createFutureLock;
        Future<BufferedInputStream> streamFuture;
    }

    public final void release()
    {
        DisconnectionRunnable disconnectionRunnable = new DisconnectionRunnable(connection,
                inputStream,
                createStreamLock,
                createFutureLock,
                streamFuture);

        synchronized (createStreamLock)
        {
            hasBeenCancelled.set(true);

            connection = null;
        }

        Thread disconnectionThread = new Thread(disconnectionRunnable);
        disconnectionThread.start();
    }

    public final int read(byte[] buffer, int numBytes)
    {
        int num = 0;

        try
        {
            synchronized (createStreamLock)
            {
                if (inputStream != null)
                    num = inputStream.read(buffer, 0, numBytes);
            }
        } catch (IOException e)
        {
        }

        if (num > 0)
            position += num;

        return num;
    }

    public final long getPosition()
    {
        return position;
    }

    public final long getTotalLength()
    {
        return totalLength;
    }

    public final boolean isExhausted()
    {
        return false;
    }

    public final boolean setPosition(long newPos)
    {
        return false;
    }

    private boolean isPost;
    private byte[] postData;
    private String headers;
    private int timeOutMs;
    String httpRequestCmd;
    private HttpURLConnection connection;
    private int[] statusCode;
    private StringBuffer responseHeaders;
    private int totalLength;
    private int numRedirectsToFollow;
    private InputStream inputStream;
    private long position;
    private final ReentrantLock createStreamLock = new ReentrantLock();
    private final Object createFutureLock = new Object();
    private AtomicBoolean hasBeenCancelled = new AtomicBoolean();

    private final ExecutorService executor = Executors.newCachedThreadPool(Executors.defaultThreadFactory());
    Future<BufferedInputStream> streamFuture;
}
